Supercritical Analysis of Waste Wood for Biodiesel Generation

( Hyeok Jin Kim ),( You Min Lee ),( Jeeban Poudel ),( Sea Cheon Oh ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 한국폐기물자원순환학회 심포지움 Vol.2019 No.1

An environmentally friendly and sustainable technology was utilized for transesterification of waste wood attributing the limitation for biodiesel production taking advantage of biomass. Literature highlights the quantitative and qualitative analysis of the wood degradation for a transesterification temperature range of 240 to 400 °C incorporating heating rates of 3.1, 9.8 and 14.5 °C/min for ethanol and 5.2, 11.3 and 16.3 °C/ min for methanol. Non-isothermal weight loss technique was taken advantage of for the kinetic analysis. A comparative analysis was carried out between the experimental values against the numerical integration results using kinetic parameters achieved in this research. The proposed method of kinetic analysis presented in this study provided decisive values of kinetic parameter for wood degradation in supercritical ethanol and supercritical methanol. In addition, this study also highlights the distinctive investigation of liquid products on elevating transesterification temperature and retention time. Carbon numbers and aromatic/aliphatic components were exercised for the categorization of the liquid products. The result demonstrated greater conversion in supercritical ethanol arises at an inferior temperature in contrast to supercritical methanol. Moreover, it also indicated that majority of products was having a carbon number range between 2 to 15.

모드 해석 방법의 절차 개발 과정 소개 및 해석 결과 비교 (MODAL, FRF, KE)

조현성(Hyunsung Jo),최재영(Jaeyoung Choi),선광상(Kwangsang Seon),박상근(Sangkeun Park) 한국자동차공학회 2022 한국자동차공학회 부문종합 학술대회 Vol.2022 No.6

During vehicle structural analysis with CAE (Computer Aided Engineering) method using FEM (Finite Element Method), the first one is the MODAL analysis. For the detail of MODAL analysis, I will explain at main chapter. The more Degree of Freedom is used in MODAL analysis, The more real flexible body motion, it have. But it needs to use more memory for the process of analysis. So, in commercial program, the Lanczos method is preferred for proceeding of mode analysis with quickly and efficiently. Using this method, it is possible to set the desired frequency interval and it can specify the number of modes you want to see. Especially, it is possible to view and evaluate natural frequency values from low-order modes such as First mode and Second mode, which are the main interests of the user, and dynamic behavior in that mode in a short time. However, as the number of parts used in the analysis model increases, it is difficult to find an accurate mode value only in the region of interest. This is because the modes of multiple parts come together with the same mode value. Especially, if the dynamic behavior you want to see is a vibration caused by a specific part, mode analysis alone is not enough. Therefore, the FRF (Frequency Response Function) method is used, which is easy to see the behavior of a particular mode of interest only, but cannot see the dynamic behavior of the mode, and it is impossible to numerically compare exactly what percentage of the mode of the desired part. Therefore, the KE (Kinetic Energy) method is used which shows exactly how much percentage each part accounts for in each mode in total mode, so it is easy to find the desired mode, and then, through mode analysis, it is possible to immediately check whether it is the desired mode or not. Therefore, in the end, for accurate mode analysis, it was previously evaluated in only one method through MODAL analysis, but now all three additional methods need to be analyzed.

Pyrolysis kinetic analysis of poly(methyl methacrylate) using evolved gas analysis-mass spectrometry

한태욱,김용민,Atsushi Watanabe,Norio Teramae,박영권,김승도 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.4

The results of evolved gas analysis-mass spectrometry (EGA-MS) analysis were used for the kinetic analysis of poly-methyl methacrylate (PMMA) pyrolysis for the first time. Various kinetic methods, such as model-free, integral master-plots, and model-fitting methods, have been applied to derive the kinetic parameters (activation energy, pre-exponential factor and reaction model). The PMMA pyrolysis reaction mechanism was suggested to occur via a single step unzipping reaction producing methyl methacrylate (MMA) as the main pyrolyzate from the kinetic analysis results and mass spectrum obtained from the EGA-MS measurements. The kinetic parameters derived from modelfree method combined with the integral master-plots method were comparable to those obtained from the peak property method (PPM). The theoretical curve derived from the kinetic results by the PPM was also well matched with the experimental thermal conversion curve using the EGA-MS measurements.

Determination of thermal decomposition kinetics of low grade coal employing thermogravimetric analysis

Prakash Parthasarathy,최항석,황재규,박훈채 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.6

The decomposition kinetics of low grade coals was studied and compared with the kinetics of higher grade coals using thermogravimetric analysis. The effect of atmospheres (air, O2 and N2) on coal decomposition kinetics was also investigated. Experiments were carried out under non-isothermal conditions from room temperature to 950 oC at a heating rate of 10 oC/min. Three kinetic models--multiple linear regression equation, unreacted shrinking core and continuous reaction--were used to determine the kinetic parameters of coal decomposition. From the kinetic parameters determined through the multiple linear regression equation, coal type and the atmosphere had an effect on coal decomposition kinetics. Also, there was some variation in the kinetic parameters of coal decomposition determined by the chosen kinetic models. However, the model employing multiple linear regressions yielded consistent results with respect to theoretical background. Under air, the order of the secondary decomposition of coal samples was found to be 0.88, 1.33, 1.69 and 1.52 for samples A, B, C and D, respectively. The order of the secondary decomposition of coal samples when operated under O2 was 1.09, 1.45, 2.36 and 1.81 for samples A, B, C and D, respectively. Under N2, the order of the secondary decomposition of coal samples was 0.72, 0.79, 1.15 and 1.02 for samples A, B, C and D, respectively.

In vito activity 와 kinetic analysis를 통한 ErmSF와 23S rRNA의 interaction mode의 연구

진형종 수원대학교 자연과학연구소 2000 자연과학논문집 Vol.3 No.-

Recently, frequent appearance of bacterial pathogens resistant to various available antibiotics is the most serious problem to the health and life of human being. One of the most plausible strategies to overcome this medical disaster is to develop the inhibitor of antibiotic resistance factor. ErmSF is a methyltransferase that confers resistance to the MLS (macrolide-lincosamide-streptograminB group) antibiotics by catalyzing the mono- or dimethylation of 23S rRNA peptidyltransferase loop at a specific N6-position of adenine residue(A2085 in Bacillus subtilis). The ermSF gene was cloned from Streptomyces fradiae NRRL2702 by PCR method and expressed to a high level in E. coli BL2l(DE3). ErmSF was obtained and purified as a soluble form in the yield of 126㎎/L culture and the enzyme efficiently methylates a 23S rRNA [Jin. H. J.(1999) Mol. Cells ]and also a 623nt transcript of domain V of 23S rRNA in vitro. Domain V of 23S rRNA was reported to have all the elements required for full erm methyltransferase activity [ Jin. H. J., et at. (1994) J. Bacteriol, 176, 6992-69981]. By progressively truncating domain V (DV, 432, 243, 66, 52, 41, 38, 27nt RNA), novel 27nt RNA minimalist substrate for ErmSF was identified, Unlike the other homologous erm proteins, ErmSF contains long N-terminal end region(71 a. a), 25% of which amino acids is composed of arginine known to interact well with RNA. From this characteristic and results of our preliminary experiments, this region is thought to interact with nucleotides of DV stems 74-79. To confirm this notion, antibiotic susceptibility assay, in vitro methylation and kinetic analysis using the wild type and the N-terminal end region truncated ErmSF and various RNAs mentioned above were carried out. Even though it confers resistance to erythromycin in E. coli, in in vitro methylation reaction, N-terminal end region truncated ErmSF showed only 30% activity compared to the wild type ErmSF in vitro. The kinetic studies performed under the conditions that only monomethylation occurs showed that the apparent Km of 243nt RNA(462 nM) and 66nt RNA(3787.5 nM) was 9 fold and 69 fold greater than the value determined for DV(44.43 nM), respectively. In addition, the Vmax for these fragments also increased 1.4 fold(1.15 pmol/min/㎎ ErmSF) and 4.2 fold(3.37 pmol/min/㎎ ErmSF) compared to that of DV(0.84 pmol/min/㎎ ErmSF). In contrast, when these RNA substrates were interacted with N-terminal end region truncated ErmSF, the Km values of DV, 243nt and 66nt RNAs were 851.32 nM, 25281.1 nM and 98096.7 nM. Vmax values were 1.59 pmol/min/㎎ ErmSF, 2.2 pmol/min/㎎ ErmSF and 40.32 pmol/min/㎎ ErmSF. When these values were compared with that obtained using the wild type ErmSF with DV, Km value were increased 17 fold, 52 fold and 2097 fold and Vmax value were also increased 1.9 fold, 2.6 fold and 49 fold. Therefore, these results suggested that N-terminal end region of ErmSF directly interact with seem 74-79 of 23S rRNA and enhance the protein-RNA interaction for methyl group accepting activity.

펜싱 런지 동작에서 주동다리와 비 주동다리의 운동역학적 특성

공세진 ( Se Jin Kong ) 한국스포츠정책과학원(구 한국스포츠개발원) 2014 체육과학연구 Vol.25 No.3

본 연구의 목적은 스포츠 영역에서 순간적인 신체의 이동 방법으로 많이 활용되는 런지 동작의 수행력에 미치는 요인을 근전도 분석이 포함된 운동역학적 분석을 통하여 규명하는 것이다. 숙련된 14명의 펜싱 선수를 대상으로 피험자가 제자리에서 최대한 멀리 나아갈 수 있는 킥 런지를 수행하게 하고 이를 3차원 동작분석기와 근전도 시스템을 적용하여 분석하였다. 킥 런지의 사전 동작이 포함된 동작과 그렇지 않은 동작을 구분하였고 이를 주동다리와 비 주동다리에서 모두 실시하였다. 이 연구의 결론은 다음과 같다. 사전 동작이 포함된 런지에서 보다 높은 수행력을 보였다. 또한 숙련도가 높아질수록 런지의 길이가 길어지는데 여기서 오는 충격량을 제어하기 위한 기전으로 운동 수행 시간을 단축하는 전략적 기전이 사용 되는 것으로 보인다. 이와 더불어 주동다리의 동작에서 모멘트와 파워 등의 역학적 변인의 차이가 나타났는데 이는 근육을 동원하는 유기적 능력의 차이에서 기인하는 것으로 보인다. The purpose of this research is to investigate the factors affecting the performance capability of lunge movements by performing lunge movements which are commonly used as a method of instant physical movement in sports with a kinetic analysis including an EMG analysis. This research targeted 14 skilled fencers and made the subjects perform kick-lunges which allow them to go farthest from their positions and performed an analysis on such, applying a 3D motion analysis system and an EMG system. The subjects performed kick-lunges in two movements; one with a preliminary movement and the other without it and those are performed with both dominant leg and non-dominant leg. The result of this research is as follows. The lunges with a preliminary movement showed higher performance capability than those without it. Furthermore, as the level of skills gets higher, the length of lunges gets longer, and it seemed that a tactical mechanism shortening exercise performance times was used as a mechanism to control the impulse coming from such lengthened lunges. In addition, a difference appeared in mechanical factors such as moment and power in a dominant leg movement and it seemed to result from a difference in an functional capability using muscles.

Kinetics of Thermal Decomposition Reactions and Changes in Structures During the Course of Carbonization of Strong Acidic Cation Exchange Resin

Hee-Chul Yang,Min Ku Jeon,Sung-Wook Kim,Maengkyo Oh 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

The process of carbonization followed by a high-temperature halogenation removal of radionuclides is a promising approach to convert low-radioactivity spent ion-exchange (IE) resins into freereleasable non-radioactive waste. The first step of this process is to convert spent ion-exchange resins into the carbon granules that are stable under high-temperature and corrosive-gas flowing conditions. This study investigated the kinetics of carbonization of cation exchange resin (CER) and the changes in structures during the course of carbonization to 1,273 K. Both of model-free and modelfitted kinetic analysis of mixed reactions occurring during the course of carbonization were first conducted based on the non-isothermal TGAs and TGA-FTIR analysis of CER to 1,272 K. The structural changes during the course of carbonization were investigated using the high-resolution FTIR and C-13 NMR of CER samples pyrolyzed to the peak temperature of each reaction steps established by the kinetic analysis. Four individual reaction steps were identified during the course of carbonization to 1,273 K. The first and the third steps were identified as the dehydration and the dissociation of the functional group of —SO3-H+ into SO2 and H2O, respectively. The second and the fourth steps were identified as the cleavage of styrene divinyl benzene copolymer and carbonization of pyrolysis product after the cleavage, respectively. The temperature and time positions of the peaks in the DTG plot are nearly identical to those of the peaks of the Gram Schmidt intensity of FTIR. The structural changes in carbonization identified by high-resolution FTIR and DTG are in agreement with those by C-13 NMR. The results of a detailed examination of the structural changes according to NMR and FTIR were in agreement with the pyrolysis gas evolution characteristics as examined by TGA-FTIR.

Kinetic study of the thermal decomposition of uranium metaphosphate, U(PO₃)₄, into uranium pyrophosphate, UP₂O₇

Yang, Hee-Chul,Kim, Hyung-Ju,Lee, Si-Young,Yang, In-Hwan,Chung, Dong-Yong ELSEVIER 2017 JOURNAL OF NUCLEAR MATERIALS Vol.489 No.-

<P><B>Abstract</B></P> <P>The thermochemical properties of uranium compounds have attracted much interest in relation to thermochemical treatments and the safe disposal of radioactive waste bearing uranium compounds. The characteristics of the thermal decomposition of uranium metaphosphate, U(PO<SUB>3</SUB>)<SUB>4</SUB>, into uranium pyrophosphate, UP<SUB>2</SUB>O<SUB>7</SUB>, have been studied from the view point of reaction kinetics and acting mechanisms. A mixture of U(PO<SUB>3</SUB>)<SUB>4</SUB> and UP<SUB>2</SUB>O<SUB>7</SUB> was prepared from the pyrolysis residue of uranium-bearing spent TBP. A kinetic analysis of the reaction of U(PO<SUB>3</SUB>)<SUB>4</SUB> into UP<SUB>2</SUB>O<SUB>7</SUB> was conducted using an isoconversional method and a master plot method on the basis of data from a non-isothermal thermogravimetric analysis. The thermal decomposition of U(PO<SUB>3</SUB>)<SUB>4</SUB> into UP<SUB>2</SUB>O<SUB>7</SUB> followed a single-step reaction with an activation energy of 175.29 ± 1.58 kJ mol<SUP>−1</SUP>. The most probable kinetic model was determined as a type of nucleation and nuclei-growth models, the Avrami-Erofeev model (A3), which describes that there are certain restrictions on nuclei growth of UP<SUB>2</SUB>O<SUB>7</SUB> during the solid-state decomposition of U(PO<SUB>3</SUB>)<SUB>4</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thermal decomposition kinetics of U(PO<SUB>3</SUB>)<SUB>4</SUB> into UP<SUB>2</SUB>O<SUB>7</SUB> was investigated. </LI> <LI> The thermal decomposition followed a single-step reaction with an activation energy of 175.3 ± 1.6 kJ mol<SUP>−1</SUP>. </LI> <LI> The most probable kinetic model was determined as a type of nucleation and nuclei-growth models, the Avrami-Erofeev (A3). </LI> </UL> </P>

Kinetic Analysis for the Catalytic Pyrolysis of Polyethylene Terephthalate Over Cost Effective Natural Catalysts

( Sumin Pyo ),( Hanie Hakimian ),( Young-min Kim ),( Kyung-seun Yoo ),( Young-kwon Park ) 한국공업화학회 2021 공업화학 Vol.32 No.6

In the current research, thermal and catalytic thermogravimetric (TG) analysis of polyethylene terephthalate (PET) over natural zeolite (NZ), olivine, bentonite, HZSM-5, and HAl-MCM-41 were investigated using a TG analyzer and model-free kinetic analysis. Catalytic TG analysis of PET was carried out at multi-heating rates, 10, 20, 30, and 40 °C/min, under nitrogen atmosphere. Apparent activation energy (Ea) values for the thermal and catalytic pyrolysis of PET were calculated using Flynn-Wall-Ozawa method. Although natural catalysts, NZ, olivine, and bentonite, could not lead the higher PET decomposition efficiency than synthetic zeolites, HZSM-5 and HAl-MCM-41, maximum decomposition temperatures on the differential TG (DTG) curves for the catalytic pyrolysis of PET, 436 °C over olivine, 435 °C over bentonite, and 434 °C over NZ, at 10 °C/min, were definitely lower than non-catalytic pyrolysis. Calculated Ea values for the catalytic pyrolysis of PET over natural catalysts, 177 kJ/mol over olivine, 168 kJ/mol over bentonite, and 171 kJ/mol over NZ, were also not lower than those over synthetic zeolites, however, those were also much lower than the thermal decomposition, suggesting their feasibility as the proper and cost-effective catalysts on the pyrolysis of PET.

Kinetic study on the nonisothermal pyrolysis of oil sand bitumen and its maltene and asphaltene fractions

Shin, Sangcheol,Im, Soo Ik,Kwon, Eun Hee,Na, Jeong-Geol,Nho, Nam Sun,Lee, Ki Bong Elsevier 2017 JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS Vol.124 No.-

<P><B>Abstract</B></P> <P>Pyrolysis is an important conversion process which can produce high value-added light oils from unconventional oils such as oil sand bitumen and extra heavy oil, thus it is important to understand the characteristics and kinetics of pyrolysis for unconventional oils. In this study, the nonisothermal pyrolysis of Athabasca oil sand bitumen and its maltene and asphaltene fractions was analyzed using a thermogravimetric analyzer, and activation energies for pyrolysis were determined by the model-free isoconversional Friedman analysis. The analysis suggests that the pyrolysis of oil sand bitumen consists of reactions for volatilization of maltene fraction and cracking of maltene and asphaltene fractions. The pyrolysis behavior of oil sand bitumen was well described based on the kinetic parameters estimated by the distributed activation energy model for maltene and asphaltene fractions, which is beneficial to effective utilization and development of pyrolysis processes of oil sand bitumen.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nonisothermal pyrolysis of oil sand bitumen and its maltene and asphaltene fractions. </LI> <LI> Determination of activation energies by model-free isoconversional Friedman analysis. </LI> <LI> Prediction of pyrolysis behavior of oil sand bitumen using kinetic parameters. </LI> </UL> </P>